1. Technical Field
The invention is in the field of solar collection, and more particularly, in the field of photovoltaic solar power.
2. Related Technology
Photovoltaic cells have typically been oriented so they point directly at the sun, to maximize the power generation efficiency. G. Agnostelli and E. J. Haverkamp, “Angular Dependency of External Quantum Efficiency on High Efficiency Solar Cells”, <http://www.rerasystems.com/pdf/ang.pdf>, describes the rapid decrease in power generation efficiency as the incidence angle increases.
Luminescent solar collectors have been proposed that will operate on a principal of an luminescent material absorbing incident sunlight and subsequently re-emitting light at a different wavelength, as described in B. C. Rowan, L. R. Wilson, and B. S. Richards, “Advanced Material Concepts for Luminescent Solar Collectors”, IEEE Journal of Selected Topics in Quantum Electronics, Vol. 14, No. 5, September 2008, pp. 1312-1322.
Concentrator photovoltaic systems are photovoltaic systems that use optical concentrators to increase the light that reaches a photovoltaic cell. One example is shown in P. A. Davies, “Design of single-surface spherical lenses as secondary concentrators for photovoltaic cells”, Pure Applied Optics, Vol. 2, p. 315-324, 1993. Other examples are shown in A. Luque, S. Hegedus, “Handbook of Photovoltaic Science and Engineering”, section 10.4 (2011). Light-focusing lenses for concentrators are manufactured by Isuzu Glass, as described at <http://www.isuzuglass.com/development/cpv.html>.
Negative index of refraction metamaterials have been demonstrated for use in the microwave regime in several recent papers, including J. B. Pendry, et al., Phys. Rev. Lett., Vol. 76 p. 4773 (1996); J. B. Pendry, et al., IEEE Trans. Microw. Theory Techniques, Vol. 47, p. 2075 (1999); and D. Smith, et al., Phys. Rev. Lett., Vol. 84, p. 4184 (2000); as well as in the 100 terahertz range in S. Linden, et. al., Science, Vol. 306, p. 1351 (2004).
Negative index of refraction materials have also been demonstrated for visible wavelengths, as described in S. P. Burgos, R. deWaele, A. Polman, and H. A. Atwater, “A single-layer wide-angle negative-index metamaterial at visible frequencies”, Nature Materials, Vol. 9, pp. 407-412, published online on Apr. 18, 2010. A theoretical basis for the materials is described in R. deWaele, S. P. Burgos, H. A. Atwater, and A. Polman, “Negative refractive index in coaxial plasmon waveguides”, Optics Express, Vol. 18, No. 12, pp. 12770-12778, 28 May 2010.